In this specification and in the appended claims, a "wall" may be horizontal, vertical, or at any desired angle; thus, a "wall" may be a floor, a ceiling, or a roof.
In new construction, whether for commercial, residential, industrial, bridge, road, or other use, it is often necessary to extend a pipe or conduit for a water, gas, or electrical line through a concrete wall. It is frequently desirable or even mandatory to provide a hydrostatic seal around the pipe or conduit to preclude seepage of water or other fluid through the wall. The most practical and effective seal construction for applications of this kind, in most instances, is an expansion seal formed of a series of interleaved blocks of rubber or other elastomer interconnected by a sequence of pressure plates, with a plurality of bolts extending between the pressure plates; the bolts are tightened to squeeze the elastomer blocks between the pressure plates, expanding the blocks to form a continuous hydrostatic seal around the pipe. A preferred construction for a wall seal closure of this kind is disclosed in U.S. Pat. No. 3,528,668 of Bruce G. Barton. Other wall closure seal constructions for forming peripheral seals on pipes and conduits are also known in the art.
To assure an effective seal, in applications of this kind, it is highly desirable and often necessary to form a passage through the wall, through which the pipe or conduit can extend, with an internal diameter large enough to afford an essentially symmetrical annular space between the pipe and the passage surface. The diameter of the wall passage may vary to a substantial extent, depending upon the outside diameter of the pipe or conduit and the particular seal to be used. Thus, the internal diameter required for the wall opening may range from under two inches to two feet or even more. For most constructions of this kind, in concrete walls, a sleeve anchored in and extending through the concrete wall has been employed.
One commercial construction uses a steel tube having a length equal to the width of the wall and having an annular steel flange welded to the outside central portion of the sleeve. Heavy wall (0.25 to 0.5 inch) steel pipe is usually used. The flange serves as a water stop that precludes water seepage along the outer surface of the sleeve, at the interface between the sleeve and the concrete wall. The flange also serves as an anchor that precludes axial movement of the wall sleeve. This steel wall sleeve construction, however, presents some substantial technical difficulties. Thus, there is a requirement for a substantial inventory of sleeves of differing lengths and diameters; the wide variations in wall width and in required sleeve diameter produce too many combinations for an economical inventory. Corrosion, cost, and sleeve weight are continuing problems.
Another wall sleeve construction, one which effectively overcomes many of the disadvantages of steel wall sleeves, is disclosed in U.S. Pat. No. 4,625,940 of Bruce G. Barton. That wall sleeve starts with a molded resin precursor having cup-like end caps of an outside diameter D formed integrally with the opposite ends of a main sleeve having an inside diameter D. In use, the end caps are cut off the main sleeve and mounted in a concrete form, with the sleeve section fitted onto the two cap sections. When the wall has been poured and set, the end caps are removed along with the concrete form, leaving a wall sleeve suitable for use with a conduit and expandable seal, as described above.
The wall sleeve precursors of U.S. Pat. No. 4,625,940 can be used to produce a long wall sleeve by cutting off the end wall of a cap section on one sleeve precursor and inserting it into the end of another precursor from which the complete cap section has been removed. But the resulting extended sleeve leaves much to be desired. At best, if the two precursors are joined by a thermal weld there is usually a ridge inside the joint and an appreciable reduction in inside diameter. The joint is not usually as strong as desired. Auxiliary fasteners such as self-tapping screws are often needed, along with a messy external sealant. Screws or other fasteners may project into the sleeve and create an appreciable obstruction in it. Labor expense is substantial, and scrap is usually undesirably high.
Another wall sleeve system, which provides appreciable improvements and affords an unobstructed wall sleeve of extended length with strong sealed joints, minimal labor costs, and no screws or other fasteners, is disclosed in Bruce G. Barton Jr. U.S. patent application Ser. No. 7/645,805 filed Jan. 25, 1991. In that system a cylindrical wall sleeve assembly forming an unimpeded passageway of consistent internal diameter through a concrete wall of given width comprises a first unitary one-piece cylindrical molded resin sleeve member having an internal diameter D1; a joint end of the first sleeve member terminates in a substantially flat radial flange having an external diameter D2, with D2&gt;D1. There is also a second unitary one-piece cylindrical molded resin sleeve member having an internal diameter D1; a joint end of the second sleeve member terminates in a substantially flat radial flange having an axially projecting outer rim with an internal diameter D2. The joint ends of the first and second sleeve members are firmly secured to each other with their radial flanges in abutting engagement to afford an assembled sleeve having an overall length approximately equal to the wall width. Finally, there are a pair of end members, each including a cylindrical body having an external diameter D1 to fit tightly into an open end of the assembled sleeve, each end member having a substantially flat radially outwardly projecting mounting flange at its outer end which limits insertion of the end member into the sleeve; the end member flanges comprise mounting means for mounting the assembly in fixed position between the opposed walls of a concrete form while allowing removal of both end members, upon dismantling of the form, for full exposure of the interior of the sleeve.
All of these systems provide passages through concrete walls that are well adapted to use with the seal of U.S. Pat. No. 3,528,688, but all have continuing problems. For steel sleeves, weight, cost, and inventory problems are principal difficulties. For resin sleeves, inadequate structural integrity in large sizes (commercial resin sleeves are pretty well limited to wall openings of less than twenty-five inches diameter) and poor bonding to the concrete, along with water leakage and through-wall fire limitations are common problems. An additional, non-technical problem, is the reluctance of some structural wall designs to use resin wall sleeves. They would rather accept the disadvantages of conventional steel sleeves than change.